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Gravimetric with High-Speed Stepper-Motor Drive

The Maguire MGF gravimetric feeder for metering colorants and additives into plastics processing machines now provides higher accuracy and up to double the throughput. Test data available comparing the enhanced MGF unit with the leading competitive gravimetric feeder indicate that when each was equipped with a half-inch auger, the Maguire device provided a wider throughput range —0.4 to 120 lb/hr compared to 1.5 to 55 lb/hr. Dosing accuracy was also greater. In tests involving 100 dispense cycles with a target of 11 grams per dose, the MGF average was exactly 11.1 grams, versus 11.3 — a 1.8% variance—for the competing feeder. This boost was achieved by replacing the continuous-rotation electric motor used for driving the feed auger with a stepper motor that completes each rotation in 200 increments and at a maximum speed of 100 rpm. In combination with digital control, the 200-step cycle achieves finer resolution in metering ingredients into the molding or extrusion process. Maguire Products Inc., Aston, PA 610-459-4300 www.maguire.com